The color correction of flash lamps is ordinarily achieved by incorporating a blue dye in either the containment coating on the light transmitting envelope or by having the blue dye incorporated into the protective cover means commonly employed with a multilamp photoflash array. In either case the dye operates as a filter reducing the light output otherwise emitted when the lamp is flashed and the amount of light loss is especially severe for a multilamp photoflash array utilizing diffuse reflector means by reason of the poor blue light reflecting ability of the pigments now used in said reflectors.
A recently developed multiple flash lamp array of the latter type is disclosed in U.S. patent application Ser. No. 825,608, Harihar D. Chevali, filed Aug. 18, 1977 and now Pat. No. 4,136,379, and assigned to the assignee of the present invention. In said patent application a planar array of flash lamps is connected to a circuit board providing switching means to cause sequential flashing of the individual lamps and having a general configuration such as earlier disclosed in another U.S. Pat. No. 3,935,442 to Hanson also assigned to the present assignee. The circuit board member disclosed in the aforementioned patent application can be made of an electrically insulative light-reflecting material such as polystyrene containing titanium dioxide pigment dispersed therein in order to have the front surface serve as a reflector thereby eliminating need for any separate reflector member in the array. Electrical circuit runs can be provided on the reflective front surface of said circuit board to permit said front surface to function in a dual capacity of carrying the flash sequencing circuitry thereon as well as reflecting light therefrom when the lamps are flashed. A transparent cover member houses the entire flash lamp array and said member can further include a blue dye incorporated in the polymer material of construction to secure any desired color correction.
Multilamp photoflash arrays having different structural configurations are also disclosed in U.S. Pat. No. 3,758,768, Roy A. Secura, and assigned to the present assignee. The protective cover means disclosed for said flash arrays is said to be suitably tinted with a blue dye to serve as an optical filter if color correction is desired. There is further mentioned in said patent of the conventional lacquer film coating such as cellulose acetate customarily employed on the exterior surface of the light-transmitting envelope of each flash lamp to provide containment protection against glass shattering when the lamps are flashed. The incorporating of blue dyes in said protective lamp coating as another means for color correction has also been recognized.